If this interest is really motivated by your desire to negotiate a higher wage I suggest you look around in your local area for pay offers for equivalent jobs, i.e. check the job listings around Prague. It'd get you an idea what you're worth locally, and if you see something that looks appealing you could at least use it to strengthen your negotiating position.

Money may well not be your purpose in life, but you gotta pay rent and put food on your family, n'est-ce pas?